1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Hello all, I've enjoyed reading the posts in the forums for a while and now I am looking for some advice regarding a set of motors I am building for my 1978 35' Cigarette Mistress. I removed a pair of merCruiser 454/400's that were already .030 over with rectangular port 990 heads and Holley carbs and Strip Dominator intakes, virtually stock. Here is what I am thinking about doing, and was advised to do by the machine shop, but I am interested in what you guys think.

Re-bore the blocks .060 over with new Scat 4340 Forged 4.250" stroker cranks to make 496CI, new Scat 4340 H-Beam connecting rods, Clevite HP rod and main bearings, Dura-Bond cam bearings, JE forged 14cc dome pistons, either at 9.5:1 or 10.25:1 compression, (I would like to retain the ability to run on 89 octane available at most marinas) Total Seal Classic Race rings, Melling HV oil pumps, Comp Cams Xtreme Marine cam kits, including cams, lifters, springs, retainers, locks, timing chains and gears, 254 @ .050 intake duration and 264 @ .050 exhaust duration with .575 intake lift and .578 exhaust lift, Manley Severe Duty 2.190” intake valves and 1.900” exhaust valves, Manley Chrome Moly Pro Series pushrods and Crane Gold wide body 1.7 ratio roller rockers, put together with ARP stainless bolts and Fel-Pro gaskets. As far as bolt-on items, I’d like to use Magnaflow cam-driven water pumps, Stainless Marine crossovers and thermostat housings, the original Strip Dominator intakes and Holley carbs, new wiring harnesses, one-wire alternators, high torque starters, all new heavy duty oil coolers and Russell hoses and fittings. For exhaust within my budget I am debating between Stainless Marine, Revolution Marine or maybe used true “tube” headers.

I’m still planning on running TRS outdrives with Speedmaster lowers, coupled to Borg Warner 72C transmissions. I plan to rebuild the transom assemblies, gimbals, drives and trannys as well because I don’t want to exceed my budget and move up to the Konrad’s just yet.

Let me know what you think of my proposed “build sheet,” I am open to all opinions as I am relatively new to this and these are the first set of engines I am building. According to the machine shop doing the work, with the above setup I should see about 600HP at 9.5:1 compression and 650+ at 10.25:1. Who knows though, only time will tell.

Thanks in advance for all of your help!

Harry
1978 Cigarette 35’ Mistress - “The Cigarette”
Palm City, Florida

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

The cam is excessively big for your application as is the 10:25 compression on 89 oct pump gas. That cam will literally be impossible to live with in your set up. Is the engine builder experienced in marine applications? Following is the cam outline and spec card. (82* overlap)
HYDRAULIC- Jet w/ B impeller, 10:1 Hyd. Hyd. 3200 to 6800 11-252-4 XM298H 298 316 254 264 .575 .578 112º
compression, river drags, Bracket Racing.
http://www.compcams.com/Technical/Se...umber=11-252-4
Bob

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Great looking boat i have a 77 35 a went thru i will email you some pics.
Great boat, solid ride, need good power to 70. If you are running 89 i would
suggest keeping compression in low 9's. I have 10-1 aluminum heads 502
and have to run premium. Good luck.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Nice boat Harry. I too have a speedmaster II on my boat and wanted to know what size props you have on it?

Thanks
Pat

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I would agree with to old step up and put a bettr roating assy. like a calies or crowler, lunati. the cam is a bit to big need around 236. int and 242. exh at .050with .580 to .600 lift on .112 food for thought

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Thanks for the advice guys, keep it coming as I am all ears! Anyone have any ideas for a cam kit that would work better? I haven't had a chance yet to look on Comp's website . . . this machine shop has built many marine motors and that was the cam kit he recommended, and he also said that the 10.25:1 compression wouldn't be too high because I was pushing the boat with two motors. Like I said, I am novice at all of this, and I want to do it right!

Thanks for the comments on the boat, it has been my lifelong goal to restore an original Aronow built Mistress and I finally got my chance. The hull was sprayed Memorial day with super jet black Awlgrip and an Awlgrip vivid red bootstripe. I'll be painting the bottom white and adding all of the graphics as on Aronow's original 32' "The Cigarette." I think it will give the boat a nice, classy, retro profile!

Hope to hear from all of you in the future!

Har

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I wouldn't run so high of compression. It won't run long on 89 with 10.25. Remember, a boat is always running uphill.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

If you're using GM iron heads, keep the comp. down to about 9.25. Flat top pistons should put you there. The biggest cam I would even think of running would be a Crane 741. On a 496 it would put your power peak up in the high 5000 rpm range. 575-600 hp is possible. If you want 650, you'll need some good ported heads.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I completely agree with RMBUILDER it seems marine engine experience may not be present We tried years ago running that piston with 10.5:1 in the old 400s when I worked at Custom Engine Service and I can tell you everyone we did with iron heads came back with burned pistons because they will not run on 89 oct for any extended period of time specially with those cams he's proposing.If you'd like I can give you some specs of 496 combos I've built and are currently running with 150 hrs that the customer has changed the oil 5 times and has not touched a single bolt on the engine apart from that. These engines made 650 hp and 620 ft lbs of torque. Please fell free to call any time and I'll give you some specs Sincerely Laz Mesa

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Nice boat. Been there, done that. I think the best bang for the buck is to find a 502EFI pullout from a performance shop and just drop it in. Add decent exhaust, maybe roller rockers, Inconel valves and you will have substantially more torque for your older, heavier boat. The added torque and cubes will offer lower cruising RPM and the EFI's have proven reliability. You also have a great platform to upgrade with. And, you'll most likely save money over what you're contemplating. Even left stock, it's a great package.

Good luck.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

For some reason I just love black boats. I am finishing up my 27 foot Magnum starfire that I just gel-coated the entire boat BLACK. It just looks mean and intimidating.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

What kind of issues will Harry have with running the Speedmasters and this kind of power?

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

He should save his money for the Conrad conversion. Speedy 2 lowers aren't any stronger than TRS. They sit lower in the water so there is no performance gain. The propeller choice is limited to cleaver designs that are very expensive. Leave the TRS and get a set of modern 5 blade props.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Dear Laz:

Thanks for the reply - if you are a former Custom Engine Service guy you must know my very good friend, Tommy McMillen. Tommy is working in Stuart, Florida at present for the local Donzi dealer and has been a good friend for almost ten years. He always recollects his Custom Engine Service days and has been a big help with this boat. If you wouldn't mind, please give me whatever you can as far as the 496's you've built, my goal, and I know this is going to sound ridiculous, is to have a reliable, relatively big power application, that will have longevity as well. If you'd like to send it to me privately, feel free to e-mail me at [email protected]. Once again, I appreciate all of the assistance I am receiving on this board!

Har

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Your TRS drives were never meant for more than 525 hp and with as heavy a boat as your Mistress is, I'd be careful with hole shots. Stay with the lower compression unless you are planning to use aluminum heads. (More maintenance in salt water.). Remember the old Hawk 500's that usually stalled when you put them in gear? (Even though they idled at 1200 RPM in neutral.)? Well, if you use the cam you described, you'll be changing it before long.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I fully understand the fact that my boat is 26 years old, and I am not looking to kill it, whether nailing it out of the hole or jumping five footers offshore at WOT . . .

My goal in building the engines is to have a boat that will cruise at a higher speed easier, rather than killing a set of smaller horsepower motors. With my original 454's I was turning roughly 4200RPM's on the tachs and barely seeing 45MPH on the GPS, although I think one engine was on its way out at that time.

As I mentioned, everything I had specified on the original post was per the machine shop proposal, and I came here to tweak it out! Also, Tommy McMillen, formerly of Custom Engine Service, has yet to go through this with me, so I am seeking his advice as well. Laz seemed to have some ideas that would work as well.

I'm sure with all of the collaborative help I'll be able to put together a dynamite set of engines! Thanks again for all of the input!

Har

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Try and design your engines/boat combo for TORQUE and to be as user friendly as possible---you'll be glad you did. I agree with what several of the others guys advice as well. Go with the better cranks. I think you'll end up being very sorry if you run 10:1+ comp ratio in your engines---especially with cast iron heads. Keep in mind the fuel octane ratings that the marinas normaly carry and that you may need 89 octane to get you home---so give yourself some cusion for error when it comes to comp ratio and remember that the gas is (or should be) the cheap part of performance boating.

I also agree that the cams you have your eye on are a bit too large. Of course you can do as you please, but I think you will appreciate good drivability/shifting, etc, while manuvering around the docks, boat traffic, currents, wind, etc. with a smaller cam than what you're speaking of. Besides, a smaller cam will give you better midrange, torque and throttle response---again, especially for a larger, heavier boat like yours.

I largest cam I would run for your engine/boat combination would be the Crane 741 hydraulic roller cams

Bowl/pocket port the heads

Switch from the single plane Dominator intake manifold to a dual plane like the Air Gap from Edelbrock or a comparable dual plane intake for such a heavy boat as a Cig.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

By the way, most of your engine mod efforts would be fruitless without a better breathing exhaust system vs the Merc cast iron exhaust manifolds which are very crude at best. I would run a full length tubular header if you can swing it. If not then one of the aftermarket hi-perf manifold designs would be the next choice such as the Stainless Marine exhaust system as you have mentioned.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

You may want to replace the heads. If they are the original, may be time to do so.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Well here's the latest, I am going to opt for either JE #142980 flat top 8.7:1 pistons, or #145376 closed chamber dome 9.1:1 pistons or #141635 open chamber dome 9.5:1 pistons. Do you think there is a significant power loss between these applications? If so, is there something else to do that would increase power at lower compression?

For my next question, I am interested in the specs on the Crane 741 and I can't seem to get them online. I'd like to find a complete kit, cam, lifters, springs, timing set, etc. as the Comp kit that I mentioned. Anybody know a part number for that?

Also, I am looking a used set of Stellings big tube headers, I think they would work nicely on the boat with the engines I am attempting to build, plus they would unclutter the engine room a little. :)

I am trying to get everything built and sorted by November so that I can take the boat to the Key West Offshore races, is anyone here going?

Thanks again for your continued help!

Har

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Because you're using iron heads, I'd advise using the 9.1 pistons. If you change to aluminum heads, the 9.5 would work because the aluminum tends to dissapate heat faster, avoiding hot spots.

You can find info on the Crane cam at www.cranecams.com. Look under marine cams. They have all of the parts required listed there. I have 2 sets of the recommended pushrods very low hours I'll sell for half price.

A bunch of us are going to Key West. Look for us, Ian and Donna. :drink:

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Okay guys . . . bear with me here :)

Can you explain in layman's terms the difference between the two cams we are discussing - the Crane 741 and the Comp XM298H.

Crane 741 = 234 @ .050 intake duration and 242 @ .050 exhaust duration and .610 intake lift and .632 exhaust lift

Comp XM298H = 254 @ .050 intake duration and 264 @ .050 exhaust duration with .575 intake lift and .578 exhaust lift

I am just trying to get a handle on what I am doing and why I am doing it, so I can go to the machine shop educated!

Also, do you know off hand if the GM rectangular port 990 heads are open chamber or closed chamber? Either way, could I safely run the JE closed chamber dome piston?

So many questions, so little time . . . and worst of all, NO boat! :hothead:

Har

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

The duration numbers at .050 are the thing to look at on these cams, although the Crane has a little more lift. The Comp cam has 20 degrees more duration. A cam with that much duration will put your power peak in a 496 at about 6500 rpm. It will cause a very poor idle at about 1000 rpm and possible stalling when you put it in gear. Also it will cause reversion with almost any wet exhaust system. The 741 has enough duration to put your power peak in the high 5000's. The idle will be choppy and loud but you should be able to idle around 800. Depending on the exhaust, the 741 may revert water.

I looked up your pistons at JE/SRP. They are a SRP number. The website says they are suitable for open or closed heads. Any heads made after about 1970 are open chamber except for the Vortech and the new 8.1.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I've done a little searching and found what I think would be a close match to the Crane 741 but in a complete Comp Cams kit.

Competition Cams Kit #K11-244-4 (244/254 & .570/.575) a.k.a. XM288H
Competition Cams Kit #K11-240-4 (234/244 & .564/.567) a.k.a. XM278H

I like the idea of these because they are relatively reasonbly priced and they are complete kits, rather than having to source out the individual parts. Is the XM288H still too big? What's the disadvantage to the lesser amount of lift as compared to the Crane? Can I run a slightly more aggressive cam and increase my idle RPM speed to increase driveability around the docks?

Hoping to figure this out so I can get the boat ready for Key West . . . November 1st is my target! :eek:

HSL

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

The Comp Cams you listed are hydraulic flat tappet cams while the Crane is a hyd. roller cam. The difference is probably 50+ horsepower. The hyd.roller costs about $800 more per engine after you buy all of the req'd. pieces. Speed costs money, how fast do you want to go?

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I argree with Laz and RMbuilder. With iron heads you need to stay around 9 to 1 with pump gas. Flat tops promote better flame travel and will make more horsepower when equal to compression of a dome piston engine. Milling the heads some will increase the compression.

Camshafts. Even for 496's everything you have posted is to large. You have a heavy boat, you need TORQUE. The runner volume on the 990's is quite large, even for 496CID's. I would suggest smaller shafts on duration, and larger lift, perferable around 600 intake and 580is on exhaust. Think of lift as what allows the engine to accerate to any given rpm and duration is the ability to sustain power at that rpm.
Duration split between intake and exhaust is determined by flow ratio of exhaust to intake. When this ratio is known, the proper amount of split can be determined for the mill. Joe Petelle of HVH and I have discussed this at length and then proven it at the track. The flow ratio is key.

Chris

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Forgot. When comparing a roller lobe to a flat tappet lobe, this is just a rule of thumb not exact, a roller lobe that is 250 degrees at .050" is equal to a hyd. that is 270 degrees at .050".

Chris

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

I think a bunch of us jumped to the conclusion that the cam in your first post was a hyd. roller. They're so common now. They do offer more power and better drivability, that's why.

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

If you're going to buy all new rotating assembly anyway why not just build a 572 right off. Sell the 454 short blocks to offset the cost of a new dart/Merlin block. You have to totally machine your old blocks anyway, and the price for a 4.25 crank is the same for a 4.5. This will help with the torque that you need. You could still bolt on your GM heads if they're in good shape or if they need alot of work try to fing a set of new/used aftermarket -- depending on your budget---
A friend of mine is running 572's in a 86 mistress and seeing 75 mph with a trs set up. You can always pull the advance back a little to ward off detonation.
I've been where you're at, do it once and make sure the person assembling knows marine :rolleyes: My 1.5 cents
Ps. you'll have to buy bigger aftermarket oil pans though, this I learned :cool:

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Cig35,

cstraub69, is right about the cams. I appologize---for some reason I kept thinking you were building 540 cubic inch engines---therefore I believe the Crane cams 741 are a bit too large for a 496. Remember, you need to build your engines for torque. Torque is what moves the mass---not horsepower! Those Cigs are HEAVY boats.

Also, if I can give you some friendly advice---not to bust your bubble, but don't be too disappointed if you don't make it by Nov 1. Building a pair of engines, putting them in the boat and getting them dialed in correctly usually takes longer than you think. There can be lots of little things that pop up that you may not be expecting, therefore I wouldn't rush it if I were you. Just take your time, do it right the first time and things will usually go a lot smoother. I am quite sure the others here would agree.

rmbuilder/Bob and/or cstraub69/Chris can probably help you get dialed in with parts/combinations and they seem to offer pretty good advice.

I do have a set of used (fresh water use only) Stellings (size/fit code color "green") full length tubular headers with approx 175-200 hours on them for sale ($2800 per set) if you're interested. There are no leaks or repair welds or anything wrong with them, and are in excellent condition. They sit a little too high in my engine compartment, but may fit/work in your Cig. You would probably have to call the Cig factory to find out if a Stellings "green" will work in your particular Cig. They are more suitable for a boat with a transmission set-up like yours vs. my Bravo One drives. So they are available.

Mark/KAAMA

Re: 1978 Cigarette 35' Mistress Project-Engine Rebuild Questions
 

Recently purchased a set of Patterson headers for this project, was wondering if anyone could give me some information about the company, and also what needs to be done to "rebuild" them to new condition.

Thanks in advance, Harry.